The present invention relates generally to systems and methods for creating maps, and more particularly, to systems and methods for calculating a location of an object using a global positioning system (GPS) receiver and a range finder. In addition, the present invention relates to systems and methods for improving the accuracy of GPS system readings.
The ability to integrate serial devices with notebook computers and new hand held computing devices like the Palm Pilot.TM., and devices running the Windows CE.TM. operating system has broadened the potential to create paperless data collection solutions. The hand held computing devices include 3Com's Palm Pilot, Casio Computer LTD's Cassiopeia, Compaq Computer Corporation's PC Companion, Ericsson Mobile Communication's MC12, Hewlett-Packard Co.'s HP Palmtop PC, Hitachi LTD's Handheld PC, LG Electronics' Phenom, NEC Computer Systems Division's MobilePro H/PC, Phillips Electronic's Velo, Sharp Electronics Corporation's Mobilon, and Vadem's Clio. Areas in which automatic data collection is useful include precision farming, asset management, resource management, civil engineering/road building, and the food service industry, to name a few.
For example, with precision farming, large farming operations world-wide can be operated with maximum cost effectiveness if reliable information about variations in the property can be mapped in a timely fashion. Projects requiring such information include the placement of irrigation and drainage systems, soil sampling, crop damage analysis, pathogen detection, and yield mapping for fertilization and pesticide use. In addition, governments and private industries that are concerned about the environment, agriculture, forestry, and mining have an ongoing need to map, inspect, regulate and monitor large areas. It can be very difficult and very time consuming to locate and map objects in these large remote areas.
Another example of an industry in which data collection and mapping is important is the utility field. Most utility companies (e.g., telephone, cable, gas, water and sewage) need to locate and map infrastructure items, such as utility poles, water meters, water lines, gas lines, and the like. The accuracy of these maps can be very important. For example, in the telecommunications industry, companies that need to run coax, fiber optic, or hybrid fiber/coax cable between existing utility poles need accurate location readings and maps of those utility poles.
Currently, these maps are made by individuals obtaining mapping information using manual surveying techniques or expensive and cumbersome surveying equipment utilizing GPS technologies. The GPS systems currently known in the art typically include custom developed data collection and manipulation devices. In addition, to use these systems, the operator must stand outside of a vehicle to obtain the proper location readings. When operators are mapping large areas, it can be extremely time consuming to drive from one mapping point to another, get outside of the car, take a reading, and then get back into the car and drive to the next location. It can be even more time consuming if the data collector is required to walk from one reading point to the next. Therefore, what is needed is an inexpensive easy to use system and method for obtaining and storing mapping information.
In addition, the accuracy of global positioning systems (GPS) is affected by a number of external influences. For example, atmospheric/ionospheric conditions, ephemeris error, receiver error, satellite clock error, multi-path error, and selective availability introduced by the Department of Defense all can affect GPS accuracy. Because of these errors, the typical accuracy of a good GPS receiver is about 60 to about 100 feet. The existence of differential corrections or differential GPS (DGPS) helps improve the accuracy to about 20 centimeters for good quality GPS receivers. Lower quality DGPS devices can have accuracies between about 1 to about 3 meters.
When recording GPS readings, it is not uncommon to see significant drift in the readings due to the above mentioned influences, even when using DGPS systems. Thus, what is need is a system and method for obtaining more accurate location readings using a GPS system, by reducing the effect of the above mentioned influences.